Process of desulfurizing coke.



ERASTUS L. STONER, OF- SOOTTDALE, PENNSYLVANIA.

PROCESS OF DESULFURIZING COKE.

Specification of Letters Patent.

Patented May 12, 1908.

Application filed November 9, 1907. Serial No. 401,407.

To all whom it may concern;

Be it known that I, ERASTUS L. STONER, a

citizen of the United States, residing at Scottdale, in the county of.VVestmoreland and State of Pennsylvania, have invented or discoverednew and useful Improvements in Processes of Desulfurizing Coke, of whichthe following is a specification.

My invention relates to processes of eliminating sulfur from coke andits object is to improve the quality of coke by removing the sulfur t0the desired limit by the use of reagents involving chlorin.

Sulfur in coal usually exists in the form of pyrites (FeS gypsum orcalcium sulfate (CaSQQ, or organic-sulfur, which is sulfur combined withthe carbon, hydrogen and oxygen of the coal.

It is my urpose in the present specification to deal on y with pyritesas it exists in the coal and is transformed to other chemical forms bythe coking processes, but it is to be understood that I do not waive theright to protection herein for all uses to which my claims may apply,whatever the character of the combinatlons with sulfur may be.

In the coke-burning processes now in use, one-half of the sulfur is,under very favorable circumstances, volatilized, if the organic sulfuris not present in excessive quantity. The sulfur expelled comes partlyfrom that which is resent in the form of organic compounds, 'ut for thelarger part form that which is present as yrites, or di-sulfid of iron,the sulfur of whlch is given ofi, even at a low temperature, as sulfurvapor. The statement in regard to one-half of the sulfur being ex elledby the usual coking processes is exemp ified by the following chemicalre action: I

in the coke is, owing to the loss in weight in the coking processincreased from one-third to one-half, so that in reality only aboutonefourth of the original per cent. of sulfur is eliminated in theordinary method of coking The organic sulfur remains for the most art inthe coke. part of the volatile sulfur will also be retained by certainconstituents of, the ash, especially com ounds of iron, such as thecarbonate, oxi and silicats, and also compounds of calcium andmagnesium. These compounds of iron are reduced in the process of cokingby compounds of carbon to the metallic condition, and this even at a lowred heat. The reduced iron, by'virtue of its powerful affinity forsulfur, combines with a part of the sulfur set free from the originalpyrites (FeS,) in the coal, to form iron sulfid (FeS).

The carbon compounds formed in the coke oven and containin sulfur, ascarbon di-sulfid (CS form sulfi s with iron and with the red-hot oxidsof the alkali metals. The sulfates resent, especially gypsum (CaSO arepartia 1y reduce to sulfids in the. oven.

My-process is based on the law that all sulfids are decomposed more orless readily by hydrochloric. acid gas (HCl), hydrogen sulfid (H 8) anda chlorid-being produced, and in some cases sulfur being alsoeliminated, and consists in chlorinating the coke preferably at or nearthe completion of the coking rocess. This process is greatly facilitated1f the sulfids are at a red heat such as is usually found in the ovensat the close of the coking process, or after the volatile matter hasbeen practically driven off. The law above stated may be illustrated bythe chemical equations in which some of the sul-' fids that form a partof the coke are used, for example:

From these formulae, it is seen that the sulfids of the coke areconverted to volatile and soluble chlorids while the sulfur passes offas hydrogen sulfid, which may later be subjected to an oxidizinginfluence. The remaining soluble chlorin salts may be washed from thecoke by the usual frwatering out processes.

Chlorin gas forms the basis of my rocess for reducing the sulfur in thecoke. his gas may be generated in any manner that best suits thecircumstances. The chlorin gas is preferably passed into superheatedsteam and then the resulting gases are applied-to the cokein' the ovens.These gases are expressed by the followingchemical reaction:

In my roces's it is definitely understood that the c lllorin gas andsuperheated steam must be transmitted. through a chamber heated tobright redness and then the resulting mixed gases of HCl and 0, whilestill in a hi hly heated condition, are applied to the coIre. 4

In my process it is essential that both the mixed gases be in a highlyheated condition and the coke red-hot, for a two-fold purpose;

first, that the various sulfids, whichmust be in such condition as hasbeen enunciated in the chemical law hereinbefore laid down,

may be readily decomposed by the HCl gas:

secondly, that the application of the gases -may haveno quenching effectu on the coke, since it is not the urgose of t e proce ess to fiienchthe coy means of the gaseous to the underlying principle of the rocess;namely, a red-hot condition of'all'su ds for a successful reductionthereof.

, In addition to the above chemical and 1 physical laws of the process,I wish to point out one other important factor. It will be noted'that itis a mixture of su erheated gases'that is sup lied to the redot coke,which is com oseil of I-ICl and O. The action of the H 61 gas has beendescribed and forms the primary feature of the process.-

The secondary chemical element is the ,free Q and its action upon thevarious compounds in the coke. The. free 0' gas, actin' meritoriously,may artly oxidize the su fids of the coke to oxi s of the respectiveelements thus freeing the sulfur as an oxid, or may Cl and 0. Such anarrangement 'would stultify and be diametrically opposed oxidize the H 8to water and an oxid of sul fur; and, acting deleteriously, the freeOgas may destroy a certain part of the carbon of the coke. a r

. I do not wish to restrict m self to any of the above reactions forfree 'It may react in any one and in all of theabove re- 7 scribed waysand in other ways not descr1 ed in the process.

By the above minutiae of the process tI- claim a new process fordesulfurizing coke,

differing materially from any process now extant. v

I do not restrict myself to any method of applying the chlorinatinggases to the coke. It may be passed through the same from the bottom orsidesor both, or from the top.

I do not restrict myself to the recise compounds with chlorin althoughhave mentioned the use of hydrochloric acid gas.

The strength of the h drochloric acid may be varied in any desire way,as by-varying' the amount of steam used withthe chlorin. I claim' if" 1. The process of treating cokemade from coal containing sulfids,which consists in subjecting the coke to the action of a chlorinatlnggas at the close of the coking process and then Watering out the fireand thereby Washing out the remaining soluble salts.

